Open Shortest Path First (OSPF) is a routing protocol developed for Internet Protocol (IP) networks by the interior gateway protocol (IGP) working group of the Internet Engineering Task Force (IETF).
Technology Information
Technology Q&A
(All IP Routing Technology Q&A)
Technology White Paper
(All IP Routing Technology White Paper)
(All IP Routing Technology Q&A)
Technology White Paper
(All IP Routing Technology White Paper)
Bidirectional Forwarding Detection for OSPF
Designing Large Scale Service Provider Dial Networks with OSPF
Designing Large-Scale Stub Networks with ODR
OSPF Configuration Management with SNMP
OSPF Database Explanation Guide
OSPF Design Guide
OSPF Overview
(PDF - 840 KB)
OSPF Redistribution Among Different OSPF Processes
OSPFv3 Summary
(PPT - 480 KB)
TCP/IP Overview
Designing Large Scale Service Provider Dial Networks with OSPF
Designing Large-Scale Stub Networks with ODR
OSPF Configuration Management with SNMP
OSPF Database Explanation Guide
OSPF Design Guide
OSPF Overview
(PDF - 840 KB)OSPF Redistribution Among Different OSPF Processes
OSPFv3 Summary
(PPT - 480 KB)TCP/IP Overview
Design
Design TechNotes
(All IP Routing Design TechNotes)
(All IP Routing Design TechNotes)
How Does Load Balancing Work?
How Does OSPF Generate Default Routes?
IP Addressing and Subnetting for New Users
OSPF Demand Circuit Feature
OSPF Neighbor States
OSPF Not-So-Stubby Area (NSSA)
Redistributing Connected Networks into OSPF
Route Selection in Cisco Routers
Route-Maps for IP Routing Protocol Redistribution Configuration
Scalable ISDN Backup Strategy for Large OSPF Networks
Specifying a Next Hop IP Address for Static Routes
Understanding Policy Routing
Using the Extended ping and Extended traceroute Commands
What Are OSPF Areas and Virtual Links?
What Does the show ip ospf interface Command Reveal?
What Does the show ip ospf neighbor Command Reveal?
What Is Administrative Distance?
When Are ICMP Redirects Sent?
How Does OSPF Generate Default Routes?
IP Addressing and Subnetting for New Users
OSPF Demand Circuit Feature
OSPF Neighbor States
OSPF Not-So-Stubby Area (NSSA)
Redistributing Connected Networks into OSPF
Route Selection in Cisco Routers
Route-Maps for IP Routing Protocol Redistribution Configuration
Scalable ISDN Backup Strategy for Large OSPF Networks
Specifying a Next Hop IP Address for Static Routes
Understanding Policy Routing
Using the Extended ping and Extended traceroute Commands
What Are OSPF Areas and Virtual Links?
What Does the show ip ospf interface Command Reveal?
What Does the show ip ospf neighbor Command Reveal?
What Is Administrative Distance?
When Are ICMP Redirects Sent?
Configure
Configuration Examples and TechNotes
(All IP Routing Configuration Examples and TechNotes)
(All IP Routing Configuration Examples and TechNotes)
Adjust Administrative Distance for Route Selection in Cisco IOS Routers Configuration Example
ASA/PIX with OSPF Configuration Example
Configuring a Gateway of Last Resort Using IP Commands
Configuring a GRE Tunnel over IPsec with OSPF
Configuring OSPF Authentication on a Virtual Link
External LSA with Overlapping Subnets in OSPF
Guide to OSPF Application on the CSS 11000
Host and Subnet Quantities
How OSPF Injects a Default Route into a Normal Area
How OSPF Injects a Default Route into a Not So Stubby Area
How OSPF Injects a Default Route into a Stub or Totally Stub Area
How OSPF Propagates External Routes into Multiple Areas
How to Populate Dynamic Routes Using Reverse Route Injection
Initial Configurations for OSPF over a Point-to-Point Link
Initial Configurations for OSPF Over Broadcast Media
Initial Configurations for OSPF over Frame Relay Subinterfaces
Initial Configurations for OSPF over Non-Broadcast Links
MPLS Basic Traffic Engineering Using OSPF Configuration Example
OSPF Inter-Area Routing
OSPF Not So Stubby Area Type 7 to Type 5 Link-State Advertisement Conversion
OSPF Routers Connected by a Multi-Access Network
OSPF Routers Connected by a Numbered Point-to-Point Link
OSPF Routers Connected by a Point-to-Multipoint Link
OSPF Routers Connected by an Unnumbered Serial Link
OSPF Virtual Link
OSPFv3 Virtual Link Configuration Example
Redistribute Connected Networks into OSPF with Subnet Keyword
Redistribute OSPFv3 Routes in BGP Configuration Example
Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP
Redistributing Routing Protocols
Sample Configuration for Authentication in OSPF
Sample Configuration for OSPFv3
Understanding Policy Routing
ASA/PIX with OSPF Configuration Example
Configuring a Gateway of Last Resort Using IP Commands
Configuring a GRE Tunnel over IPsec with OSPF
Configuring OSPF Authentication on a Virtual Link
External LSA with Overlapping Subnets in OSPF
Guide to OSPF Application on the CSS 11000
Host and Subnet Quantities
How OSPF Injects a Default Route into a Normal Area
How OSPF Injects a Default Route into a Not So Stubby Area
How OSPF Injects a Default Route into a Stub or Totally Stub Area
How OSPF Propagates External Routes into Multiple Areas
How to Populate Dynamic Routes Using Reverse Route Injection
Initial Configurations for OSPF over a Point-to-Point Link
Initial Configurations for OSPF Over Broadcast Media
Initial Configurations for OSPF over Frame Relay Subinterfaces
Initial Configurations for OSPF over Non-Broadcast Links
MPLS Basic Traffic Engineering Using OSPF Configuration Example
OSPF Inter-Area Routing
OSPF Not So Stubby Area Type 7 to Type 5 Link-State Advertisement Conversion
OSPF Routers Connected by a Multi-Access Network
OSPF Routers Connected by a Numbered Point-to-Point Link
OSPF Routers Connected by a Point-to-Multipoint Link
OSPF Routers Connected by an Unnumbered Serial Link
OSPF Virtual Link
OSPFv3 Virtual Link Configuration Example
Redistribute Connected Networks into OSPF with Subnet Keyword
Redistribute OSPFv3 Routes in BGP Configuration Example
Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP
Redistributing Routing Protocols
Sample Configuration for Authentication in OSPF
Sample Configuration for OSPFv3
Understanding Policy Routing
Troubleshoot and Alerts
Troubleshooting TechNotes
(All IP Routing Troubleshooting TechNotes)
(All IP Routing Troubleshooting TechNotes)
Common Routing Problem with OSPF Forwarding Address
Configuring a Gateway of Last Resort Using IP Commands
External LSA with Overlapping Subnets in OSPF
Guide to OSPF Application on the CSS 11000
Host and Subnet Quantities
How Does Load Balancing Work?
How Does OSPF Generate Default Routes?
Initial Configurations for OSPF over Non-Broadcast Links
IP Addressing and Subnetting for New Users
OSPF and EIGRP Neighbor Loss, RIP and IGRP Update Loss after Upgrading to Cisco IOS 11.2 or Later
OSPF Demand Circuit Feature
OSPF Neighbor Problems Explained
OSPF Neighbor States
OSPF Not-So-Stubby Area (NSSA)
OSPF show Commands Respond Slowly
OSPF, MTU and LSA Packing Tech Note
Problems with Running OSPF in NBMA and Broadcast Mode over Frame Relay
Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP
Redistributing Connected Networks into OSPF
Redistributing Routing Protocols
Route Selection in Cisco Routers
Route-Maps for IP Routing Protocol Redistribution Configuration
Scalable ISDN Backup Strategy for Large OSPF Networks
Specifying a Next Hop IP Address for Static Routes
Suboptimal Routing When Redistributing Between OSPF Processes
The "%TUN-5-RECURDOWN" Error Message and Flapping EIGRP/OSPF/BGP Neighbors Over a GRE Tunnel
The Effects of the Forwarding Address on Type 5 LSA Path Selection
Troubleshooting Duplicate Router IDs with OSPF
Troubleshooting OSPF
Understanding Policy Routing
Using the Extended ping and Extended traceroute Commands
What Are OSPF Areas and Virtual Links?
What Do %OSPF-4-ERRRCV Error Messages Mean?
What Does the show ip ospf interface Command Reveal?
What Does the show ip ospf neighbor Command Reveal?
What Is Administrative Distance?
When Are ICMP Redirects Sent?
Why Are OSPF Neighbors Stuck in Exstart/Exchange State?
Why Are Some OSPF Routes in the Database but Not in the Routing Table?
Why Does the show ip ospf neighbor Command Reveal Neighbors in the Init State?
Why Does the show ip ospf neighbor Command Reveal Neighbors Stuck in Two-Way State?
Why Doesn't OSPF Form Adjacency on a PRI, BRI, or Dialer Interface?
Why OSPF Demand Circuit Keeps Bringing Up the Link
Configuring a Gateway of Last Resort Using IP Commands
External LSA with Overlapping Subnets in OSPF
Guide to OSPF Application on the CSS 11000
Host and Subnet Quantities
How Does Load Balancing Work?
How Does OSPF Generate Default Routes?
Initial Configurations for OSPF over Non-Broadcast Links
IP Addressing and Subnetting for New Users
OSPF and EIGRP Neighbor Loss, RIP and IGRP Update Loss after Upgrading to Cisco IOS 11.2 or Later
OSPF Demand Circuit Feature
OSPF Neighbor Problems Explained
OSPF Neighbor States
OSPF Not-So-Stubby Area (NSSA)
OSPF show Commands Respond Slowly
OSPF, MTU and LSA Packing Tech Note
Problems with Running OSPF in NBMA and Broadcast Mode over Frame Relay
Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP
Redistributing Connected Networks into OSPF
Redistributing Routing Protocols
Route Selection in Cisco Routers
Route-Maps for IP Routing Protocol Redistribution Configuration
Scalable ISDN Backup Strategy for Large OSPF Networks
Specifying a Next Hop IP Address for Static Routes
Suboptimal Routing When Redistributing Between OSPF Processes
The "%TUN-5-RECURDOWN" Error Message and Flapping EIGRP/OSPF/BGP Neighbors Over a GRE Tunnel
The Effects of the Forwarding Address on Type 5 LSA Path Selection
Troubleshooting Duplicate Router IDs with OSPF
Troubleshooting OSPF
Understanding Policy Routing
Using the Extended ping and Extended traceroute Commands
What Are OSPF Areas and Virtual Links?
What Do %OSPF-4-ERRRCV Error Messages Mean?
What Does the show ip ospf interface Command Reveal?
What Does the show ip ospf neighbor Command Reveal?
What Is Administrative Distance?
When Are ICMP Redirects Sent?
Why Are OSPF Neighbors Stuck in Exstart/Exchange State?
Why Are Some OSPF Routes in the Database but Not in the Routing Table?
Why Does the show ip ospf neighbor Command Reveal Neighbors in the Init State?
Why Does the show ip ospf neighbor Command Reveal Neighbors Stuck in Two-Way State?
Why Doesn't OSPF Form Adjacency on a PRI, BRI, or Dialer Interface?
Why OSPF Demand Circuit Keeps Bringing Up the Link
